Why do we need iron in our diet?
The minerals required by our bodies are needed in very tiny amounts, and many minerals become poisonous in higher concentrations. For example, iron is essential to make haemoglobin and blood, but drinking too much iron in water, or an overdose as few as 20 of the iron tablets used to treat anaemia, can be enough to kill.
So our bodies have developed very clever ways to maintain the balance of supply and need:
- Our small intestines regulate the amount of iron we absorb from foods, depending on how much is present in the diet, and how much the body needs at that particular time.
- We generally remove excess iron in the stools.
- Vegetarian diets contain little iron, but by eating lots of vitamin C at the same time, vegetarians actually absorb a greater proportion of the iron in their foods.
- And we can store quite large amounts of iron in our livers, to use if dietary supply drops for a time.
So although the amount of iron in human diets varies widely across the world, we can function well with a wide range of iron. Nonetheless, many people, menstruating women and children in particular, are anaemic because there is insufficient iron in their diets.
Why do we need it?
Where do we find it?
To transfer oxygen between tissues in our body. Most iron in our body is in haemoglobinin blood cells or myoglobin in muscle (two proteins that carry oxygen).
Iron is also essential for a healthy immune system and in some enzymes.
Deficiency is common, especially in young people and menstruating women.
Best absorbed is ‘haem iron’, present in meat and fish.
‘Non-haem iron’, in plant foods such as cereals, is less well absorbed. There is very little in vegetables like spinach!
Vitamin C improves the absorption absorption of non-haem iron.